1. Technical Fields
The present invention relates to an image forming apparatus and a transfer device having a belt-shaped image carrier and a transfer roller formed with a concaved portion on a peripheral surface thereof.
2. Description of the Related Art
As an image forming apparatus configured to transfer an image formed on an image carrier to a recording material, those disclosed, for example, in JP-T-2000-508280 (for example, FIG. 1 and FIG. 2A) and JP-T-2002-530722 (for example, FIG. 4) may be exemplified. The apparatuses disclosed in these publications are the image forming apparatuses of a type which visualizes electrostatic latent images with liquid developer containing toner particles and carrier liquid, so called, a liquid-developing system. In these apparatuses, an image is transferred to the recording material by gripping the recording material with a gripper (gripping portion) provided on part of the peripheral surface of a press roller (which corresponds to a transfer roller), and feeding the recording material though a nip with respect to a drum-shaped intermediate transfer member (image carrier) while winding the same around the press roller.
In the related art described above, the image formed on a photoconductor drum is primarily transferred to the intermediate transfer member, and then is secondarily transferred to the recording material which is passed through the nip (transfer nip) formed by the press roller and the intermediate transfer member abutting each other. In this manner, in the structure in which a photosensitive member and the press roller both come into contact with the drum-shaped intermediate transfer member, vibrations or velocity fluctuations generated at the transfer nip may be transmitted to the photosensitive member and cause distortion of image when the recording material enters the transfer nip or while the recording material is passing through the transfer nip, and hence the quality of the image may be degraded. In particular, when a concaved portion for disposing the gripping portion is provided on the peripheral surface of the press roller, this problem is apparent.